Pump assembly especially for dishwashing machines

ABSTRACT

Pump assembly includes in combination a rotary pump of the radial type and an axial pump, having respective rotors both mounted on a common shaft so that each of the pumps runs in reverse when the other thereof runs forward, the rotary pump having an induction opening and, in reverse running condition, being adapted adapted to drive water partially filling the rotary pump in reverse through the induction opening, the axial pump being self-inducting, insensitive to foreign bodies and dependent upon rotary direction.

United States Patent [72] Inventors SiegfriedSchiinwald S mm T H m N n m E m W mu P Wm C s m a SE w s. a T t m n .e w rl es I. e a THL E w W999 H 242 7 5 905 645 1 182 6 U 233 Martin-Luther-Str. 44;

Gert Hecht, Berliner Str. 23, Bad Neustadt Saale; Gunther Krampz, Zehnstr. 4. Burglauer: Rudolf Schiining, Martinpening and, in reverse Luther-Str. 48, Bad Neustadt, Saale, all of Germany FOREIGN PATENTS [2|] Appl. No. 809,798 420,324 4/1947 ltaly [22] 1969 Primary Examinerl-lenry F. Raduazo [45] Patented June 8, 19 1 Attorneys-Curt M. Avery, Arthur E. Wilfond, Herbert L. [32] Priority Mar. 26, 1968, Mar. 30, 1968 Lerner and Daniel Tick [33] Germany 1 P 17 03 046.5 and P 17 03 090.9

[54] PUMP ASSEMBLY ESPECIALLY FOR ABSTRACT: Pump assembly includes in combination a rotary DISHWASHING MACHINES pump of the radial type and an axial pump, having respecti a Chums 7 Drawing Figs rotors both mounted on a common shaft so that each of the pumps runs in reverse when the other thereof runs forwa the rotary pump having an induction 0 running condition, being adapted adapted to drive water partially filling the rotary pump in reverse through the induction opening, the axial pump being self-inducting, insensitive to foreign bodies and dependent upon rotary direction.

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ATENTFB JUN 97;

SHEET 2 BF 3 PATENTEU JUN 8 1971 SHEET 3 OF 3 PUMP ASSEMBLY ESPECIALLY FOR DISHWASHING MACHINES Our invention relates to pump assembly, especially for dishwashing machines.

As is generally known, two pumps are required for dishwashing machines, namely a circulating pump for spraying the rinsing water on the dishes, and a drain pump for discharging the dirty water between the individual rinsing stages.

For reasons of space limitation as well as for reducing costs, it is desired to replace the two separate pumps with a single pump assembly which fulfills both of the aforementioned functions.

It is accordingly an object of our invention to provide pump assembly, especially for dishwashing machines, which requires considerably less space than that required by the two separate pumps employed heretofore in dishwashers, and which costs considerably less than the two separate pumps employed heretofore for the same functions.

With the foregoing and other objects in view we provide pump assembly comprising in combination a rotary pump of the radial typeand an axial pump, both mounted on a common shaft, the pumps having motors so disposed on the shaft that each of the pumps runs in reverse when the other thereof is in delivery stage, the rotary pump having an induction opening and, in reverse running stage being adapted to drive water partially filling the rotary pump in reverse through the induction opening, the axial pump being self-inducting, insensitive to foreign bodies and dependent upon rotary direction.

According to a further feature of our invention, both pumps of the assembly are mounted in a common housing which is divided by a partition disposed between both pump rotors.

According to other features of our invention, the rotary pump of the assembly comprises a rotor, a pump chamber surrounding the rotor and having a defining wall, an induction passage having an opening coaxial with the rotor and communicating with the pump chamber, a pressure duct communicating with the pump chamber and having an inner wall intersecting the defining wall of the pump chamber, and a tongue extending from the intersection of the walls toward the rotary pump rotor so that in reversely running stage of the rotary pump rotor a water ring forming in the pump chamber is inwardly deflected by the tongue so as to partly overlap the induction passage opening. Thus, when only partly filled with water, the rotary pump running in reverse does not drive water through the pressure duct but rather through the induction passage or duct.

According to additional features of our invention, the axial pump of the assembly comprises annular induction and pressure chambers on axially opposite sides of the rotor of the axial pump, both of the annular chambers being interrupted by a respective wall, an annular stabilizing chamber for separating water-air mixture during induction stage after-connected to the pressure chamber, the stabilizing chamber being adapted to contain water necessary for self-induction and being adapted to reconvey the water therethrough to the induction and pressure chambers. By this construction the conditions are met that the axial pump is self-inducting and insensitive to foreign bodies as well as dependent upon rotary direction in both directions or only delivers water from induction duct to the pressure duct in one rotary direction. The lastmentioned feature is of importance so that the axial pump acting as a drain pump, when running in reverse i.e. when the rotary pump acting as a circulation pump, delivers or drives the water, does not again induct or suck the rinsing water back in,

Other features which are considered as characteristic for the invention are set forth in the appended claims.

Although the invention is illustrated and described herein as embodied in pump assembly especially for dishwashing machines, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.

The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, in which:

FlG. l is a longitudinal cross section of the pump assembly of our invention;

FlG. 2 is a cross-sectional and schematic view of the radial pump portion located at the left-hand side of FIG. 1;

FIG. 3 is a longitudinal sectional and schematic view of the axial pump portion located at the right-hand side of FIG. 1;

FIG. 4 is a sectional view of FIG. 3 taken along the line lV-lV in the direction of the arrows;

FlG. 5 is a sectional view of FIG. 3 taken along the line V-V in the direction'of the arrows and showing the flow lines for the suction stage of operation thereof;

FIG. 6 is a view corresponding to that of FIG. 5 but showing the flow lines purely for the water delivery stage; and

FIG. 7 is a sectional view of FIG. 6 taken along the line lV-lV.

Referring now to the drawings, and first particularly to F IG. 1 thereof, there is shown a housing 1 of the pump assembly of our invention, which has an intermediate partition 2 that divides the interior into two separate pump chambers 3 and 4, in which pump rotors 5 and 6 are respectively mounted by a common hub 7 on a shaft 8. Thus, two pumps are provided in combination, a component pump 9 shown at the left-hand side of FIG. 1 being in the form of a rotary pump of the radial type, and a component pump 10 shown at the right-hand side of FIG. 1 being in the form of an axial pump. Both component pumps 9 and 10 are described hereinafter in greater detail. Between the intermediate partition 2 and the hub 7 there is located an annular gap 11 which is sealed by a glide-ring seal or lip seal 12. The seal 12 consists of an elastic rubber ring forming an integral part of the pump rotor 5 or the hub 6 thereof i.e. both the entire pump rotor 6 as well as the glidering seal 12 laterally seated thereon are formed of rubber. A spring-loaded glide-ring seal 13 seals the pump chamber 4 from the shaft 8.

The pump assembly of our invention operates as follows: When the rotary pump 9 delivers water, for example as a circulating pump in a dishwasher, water penetrates into the gap 11, raises the seal 12 slightly from the intermediate partition 2 and passes into the pump chamber 4 for cooling the glide-ring seal 13. Since the axial pump 10 runs in reverse, it does not deliver or drive the water out of the pressure duct but rather backwards into the nonillustrated common collection vessel of the dishwasher. Contrarily, if the water is being delivered or driven by the axial pump 10 operating as a drain pump in a dishwashing machine, the seal 12 is then subjected to pressure from the axial pump 10 and seals the gap 11. if water nevertheless passes through the gap 11 into the pump chamber 4, the reversely running rotary pump 9, due to its structure, delivers or drives this water through the suction opening again into the common drain.

The pump assembly of our invention though provided primarily for dishwashing machines, is nevertheless obviously not limited to this use alone.

The rotary pump chamber 3 of FIG. 1 is identified by the reference numeral 21 in FIG. 2, and the pump rotor 5 of FIG. 1 is identified by the reference numeral 22. The rotary pump 9 is provided with a pressure duct 23 and with a suction opening 24. A tongue 27 formed at the intersection of the inner wall 25 of the pressure duct 23 and the pump chamber wall 26 is curved sharply inwardly so as to extend close to the periphery of the rotor 22. Due to this curved tongue 27, the water ring circulating in the pump chamber 21 when the latter is only partly filled with water and whose inner contour is represented in FIG. 2 by the dotted line 28, is deflected inwardly when the pump rotor runs in reverse as indicated by the associated curved arrow. Thereby, the water ring overlaps the suction opening 24 as indicated by the shaded area 29. Thus when water is admitted to the pump 9 by any means and in any manner, this water is then respectively driven out through the suction opening 24, while the water column 30 in the pressure duct 23 does not exceed a predetermined low level.

The construction and operation of the axial pump 10 is further described hereinafter with reference to FIGS. 3 to 7. The axial pump 10, as shown in FIG. 3, has a housing 31. The drive shaft 32 and pump rotor 33 of FIG. 3 respectively correspond to the shaft 8 and pump rotor 6 of FIG. I. On both axial sides of the rotor 33 of FIG. 3 there is provided in the housing 31 a respective working chamber, namely an induction or suction chamber 34, with which the induction or suction opening 35 communicates, and a pressure chamber 36. Both chambers 34 and 36 are of ring-shaped construction, and are connected to one another through the rotor 33. According to our invention, the rotation of the flow in both chambers 34 and 36 is cut off by an interrupter wall 37 (FIG. and 38 (FIG. 7). Furthermore, a stabilizing chamber 39 is after-connected to the pressure chamber 36 and is of ring-shaped construction and surrounds the pressure chamber 36. The pressure duct opening 40 is connected to this stabilizing chamber 39. As shown in FIG. 5, the pressure chamber 36 and the stabilizing chamber 39 are interconnected through openings 41 and 42 that are located on both sides of the interrupter wall 38 in the pressure chamber 36.

At start-up of the pump assembly of our invention, the following operation occurs: air is initially inducted through the induction or suction duct 35 into the induction or suction chamber 34. The water which always remains in the pump is indicated by the dotted region located in the lower part of the stabilizing chamber 39 as shown in FIG. 5. This water flows through the opening 41 into the adjacent pressure chamber 36 and through the rotor 33 in turn to the induction or suction chamber 34. When the water impinges on the air inducted through the duct 35 into the chamber 34, a water-air mixture is formed under the action of the rotating pump rotor 33 and driven thereby again into the pressure chamber 36. From the pressure chamber 36, the water-air mixture flows at great velocity through the opening 42 into the beginning of the stabilizing chamber 39 and sweeps thereover the rib 43. Thereby, the water is directed away from the outlet opening 40 and back again into the stabilizing chamber 39 while part of the air escapes through the opening 40. A further intermixture then occurs when the air-water mixture with the remaining air then impinges on the water standing in the chamber 39, so that from there a part of the remaining air again flows back and discharges from the duct 40. This circulatory flow continues until the induction or suction stage ends and the pump delivers or drives water only. Since the circulatory flow is also maintained during the delivery or drive of water only, air bubbles are always eliminated.

We claim:

1. Pump assembly comprising in combination a rotary pump of radial type and an axial pump having respective rotors both mounted on a common shaft so that each of said pumps runs in reverse when the other thereof runs in forward direction, a hub carried by said common shaft, both said rotors in common being mounted on said hub, said rotary pump having an induction opening and, in reverse running condition thereof, being adapted to drive water partially filling the rotary pump in reverse through said induction opening, said axial pump being self-inducting, insensitive to foreign bodies and dependent upon rotary direction, a common housing for both said pumps, said housing being subdivided by an intermediate partition, said intermediate partition being disposed between said rotors and surrounding said hub, sealing means carried by said hub and abutting said intermediate partition, said sealing means being located on the side of said intermediate partition on which said axial pump is located, said axial pump including a pressure chamber and an induction chamber on opposite sides of the rotor thereof, said sealing means being located in said pressure chamber of said axial pump and being formed of elastic material, and additional sealing means located in said induction chamber of said axial pump for sealing said induction chamber from said shaft, said first-mentioned sealing means being yreldable III forward running condition of said rotary pump for admitting water to said axial pump for cooling said additional sealing means.

2. Pump assembly according to claim 1 wherein said sealing means comprises a glide-ring seal.

3. Pump assembly according to claim 1 wherein said sealing means comprises an annular lip seal.

4. Pump assembly comprising in combination a rotary pump of radial type and an axial pump having respective rotors both mounted on a common shaft so that each of said pump runs in reverse when the other thereof runs in forward direction, a hub carried by said common shaft, both said rotors in bommon being mounted on said hub, said rotary pump having an induction opening and, in reverse running condition thereof, being adapted to drive water partially filling the rotary pump in reverse through said induction opening, said axial pump being self-inducting, insensitive to foreign bodies and dependent upon rotary direction, a common housing for both said pumps, said housing being subdividedby an intermediate partition, said intermediate partition being disposed between said rotors and surrounding said hub, sealing means carried by said hub and abutting said intermediate partition, said sealing means being located on the side of said intermediate partition on which said axial pump is located, said sealing means and the rotor of said axial pump being an integral member formed of rubber.

5. Pump assembly comprising in combination a rotary pump of radial type and an axial pump having respective rotors both mounted on a common shaft so that each of said pumps runs in reverse when the other thereof runs in forward direction, said rotary pump having an induction opening and, in reverse running condition thereof, being adapted to drive water partially filling the rotary pump in reverse through said induction opening, said axial pump being self-inducting, insensitive to foreign bodies and dependent upon rotary direction,lsaid axial pump including an annular pressure chamber and an annular induction chamber on opposite sides of the rotor thereof, and a stabilizing chamber after-connected to said pressure chamber for separating a water-air mixture admitted thereto during an induction stage of operation of said axial pump, said stabilizing chamber being adapted to contain an adequate amount of water for self-priming and to thereby resupply the water to said pressure chamber.

6. Pump assembly according to claim 5 including a transversely extending wall in said annular pressure and induction chambers, respectively, said wall, respectively, interrupting said chambers.

7. Pump assembly according to claim 6 wherein said stabilizing chamber is connected to said pressure chamber on both sides of said interrupting wall in said pressure chamber.

8. Pump assembly according to claim 7 including a pressure duct for said axial pump communicating with-said stabilizing chamber on one side of the interrupting wall in said pressure chamber, and guide means disposed in said stabilizing chamber between said pressure duct and the connection between said pressure chamber and said stabilizing chamber on said one side of said interrupting wall for diverting water flowing in said stabilizing chamber from said pressure duct. 

1. Pump assembly comprising in combination a rotary pump of radial type and an axial pump having respective rotors both mounted on a common shaft so that each of said pumps runs in reverse when the other thereof runs in forward direction, a hub carried by said common shaft, both said rotors in common being mounted on said hub, said rotary pump having an induction opening and, in reverse running condition thereof, being adapted to drive water partially filling the rotary pump in reverse through said induction opening, said axial pump being self-inducting, insensitive to foreign bodies and dependent upon rotary direction, a common housing for both said pumps, said housing being subdivided by an intermediate partition, said intermediate partition being disposed between said rotors and surrounding said hub, sealing means carried by said hub and abutting said intermediate partition, said sealing means being located on the side of said intermediate partition on which said axial pump is located, said axial pump including a pressure chamber and an induction chamber on opposite sides of the rotor thereof, said sealing means being located in said pressure chamber of said axial pump and being formed of elastic material, and additional sealing means located in said induction chamber of said axial pump for sealing said induction chamber from said shaft, said first-mentioned sealing means being yieldable in forward running condition of said rotary pump for admitting water to said axial pump for cooling said additional sealing means.
 2. Pump assembly according to claim 1 wherein said sealing means comprises a glide-ring seal.
 3. Pump assembly according to claim 1 wherein said sealing means comprises an annular lip seal.
 4. Pump assembly comprising in combination a rotary pump of radial type and an axial pump having respective rotors both mounted on a common shaft so that each of said pump runs in reverse when the other thereof runs in forward direction, a hub carried by said common shaft, both said rotors in common being mounted on said hub, said rotary pump having an induction opening and, in reverse running condition thereof, being adapted to drive water partially filling the rotary pump in reverse through said induction opening, said axial pump being self-inducting, insensitive to foreign bodies and dependent upon rotary direction, a common housing for both said pumps, said housing being subdivided by an intermediate partition, said intermediate partition being disposed between said rotors and surrounding said hub, sealing means carried by said hub and abutting said intermediate partition, said sealing means being located on the side of said intermediate partition on which said axial pump is located, said sealing means and the rotor of said axial pump being an integral member formed of rubber.
 5. Pump assembly comprising in combination a rotary pump of radial type and an axial pump having respective rotors both mounted on a common shaft so that each of said pumps runs in reverse when the other thereof runs in forward direction, said rotary pump having an induction opening and, in reverse running condition thereof, being adapted to drive water partially filling the rotary pump in reverse through said induction opening, said axial pump being self-inducting, insensitive to foreign bodies and dependent upon rotary direction, said axial pump including an annular pressure chamber and an annular induction chamber on opposite sidEs of the rotor thereof, and a stabilizing chamber after-connected to said pressure chamber for separating a water-air mixture admitted thereto during an induction stage of operation of said axial pump, said stabilizing chamber being adapted to contain an adequate amount of water for self-priming and to thereby resupply the water to said pressure chamber.
 6. Pump assembly according to claim 5 including a transversely extending wall in said annular pressure and induction chambers, respectively, said wall, respectively, interrupting said chambers.
 7. Pump assembly according to claim 6 wherein said stabilizing chamber is connected to said pressure chamber on both sides of said interrupting wall in said pressure chamber.
 8. Pump assembly according to claim 7 including a pressure duct for said axial pump communicating with said stabilizing chamber on one side of the interrupting wall in said pressure chamber, and guide means disposed in said stabilizing chamber between said pressure duct and the connection between said pressure chamber and said stabilizing chamber on said one side of said interrupting wall for diverting water flowing in said stabilizing chamber from said pressure duct. 